Published in Geotechnical and Geological Engineering
Volume 24, Issue 6, December 2006, Pages 1749-1765

Archived in Dspace@nitr http://dspace.nitrkl.ac.in/dspace

GEOTECHNICAL CHARACTERISATION OF FLY ASH COMPOSITES FOR BACKFILLING MINE VOIDS

Manoj Kumar Mishra^†*  U.M.Rao Karanam^‡

^† Department of Mining Engineering, National Institute of Technology-Rourkela-769 008, India
^‡ Department of Mining Engineering, Indian Institute of Technology-Kharagpur 721 302, India
*Corresponding Address: Tel. +91-661-2470278; Fax 91-661-2472926; mkmishra@nitrkl.ac.in.

ABSTRACT

Back filling of mine voids is mandatory to avoid subsequent ground stability problems in the form of subsidence. River sand and mill tailings have been widely used since a long time as back filling materials. However with a strict regulation banning river sand mining in India, research for developing alternative engineering materials substituting sand has gained importance. In the present study four fly ash composite materials (FCMs) was developed from the fly ash obtained from a captive thermal unit of Rourkela Steel Plant(RSP). The main constituent of the composite were fly ash, lime and gypsum. Detailed physical, and engineering properties were determined for the FCMs. Significant increases in the compressive strength were obtained after 56 days of curing time. A detailed SEM studies was undertaken to account for the increase in strength with time. The fly-ash composite developed from RSP has potential to be used as substitute to sand for back filling the mine voids.

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